To be quite honest, this is a subject, with my facination for Star Trek, that I have followed for many years. It is also a subject, that with the many zelous Sci-Fi lovers, who happen to become scientists, can be tainted with disinformation and fabrication of evidence.
The reports and studies that I have read, and believe to hold some degree of credibility, all indicate the that antimatter is not actaully matter, but more the lack of matter in a place where there should be such.
The most famous, at least to those in the field, experiment done was something like the following (I will water it down a lot, since part of it was a 45 page writeup about a magnet...)
First lets establish the things we know about matter:
1) It cannot be "created" or "destroyed" (Law of Conservation of Mass). I put those in quotes, since they are very relative terms.
2) Matters physical space is mass, and under any gravity, is a constant value.
3) (This one is somewhat hypothetical still, but quantum mechanics is still a relatively new science, so some day it might be a law) Matter seems to be made up of an infinite number of decreasingly small components.
So, knowing that, consider the following.
Basically, the best known way of "generating" antimatter is to apply a beam of high energy photons to an extremely dense magenetic field between a set of plates. These plates are extremely close together, and interestingly enough, require extreme cooling for the experiment to be done properly. Now, between the plates is a gas of know type, mass, and isotope, to which the beam is applied. The distance between the plates is as such that as the gas is energized from the beam of photons, there isn't enough room between the plates for the generation of new photons.
For those who have forgotten, when a photon strikes an atom, it moves or "knocks" the atom's electrons into a higher orbital, or sometimes entirely off of the atom. During this process the photon is converted to the engery required to move the electron. When the electron fails to maintain its high energy state, and succumbs to the strong and weak forces in the atom's nucleus, it falls back down to its original or "ground" state. This process releases a new photon, there by generating electromagnetic radiation, in the various forms of visible light, alpha, beta and gamma radiation, etc.
As I said though, the possitioning of the plates prevents this last part from happening though, which is a violation of the Law of Conservation of Mass, since we "destroyed" a photon. The only reasonable and logical conclusion is, that by preventing formation of new photons, an alternate partical, in this case an anti electron.
The problem with antimatter is, to be reasonably contained, at the current time, it must be immediately isolated from matter, or it will immediately react with that mater, and annihilate.
Now, the reason you get a null area during a reaction is because you end up with particals with a spin that doesn't follow standard patterns. Yes, this could be harnessed for energey, by all means. It would be a lot like take magnets of the same pole, shoving them together and then holding them there. If you do that, the magnets in your hands will never come into contact, because the force required to move them closer rises exponentally as they get closer. The same would apply here, which is why scientists think that massive energy would be released in a matter/antimatter reaction. The result though, would be nuetrally charged particals, which, according to quantum mechanics, would most likely decay back into standard matter over some period of time.
The questions the next generation has to answer is how to generate antimatter efficently, how to contain it, and at what point is the released energy harnessable.
Boy... my fingers hurt.... LOL